The move comes a day after Harvard University sued the Trump administration, which has threatened to cut funding and impose outside political supervision.

“We speak with one voice against the unprecedented government overreach and political interference now endangering American higher education,” the letter read.

“We are open to constructive reform and do not oppose legitimate government oversight. However, we must oppose undue government intrusion,” it said, adding: “We must reject the coercive use of public research funding.”

Trump has sought to bring several prestigious universities to heel over claims they tolerated campus anti-Semitism, threatening their budgets, tax-exempt status and the enrolment of foreign students.

The letter said the universities and colleges were committed to serving as centres where “faculty, students, and staff are free to exchange ideas and opinions across a full range of viewpoints without fear of retribution, censorship, or deportation.”

Trump’s war against universities has seen him threaten to cut federal funding over policies meant to encourage diversity among students and staff.

The Republican president has also pursued a wide-ranging immigration crackdown that has expanded to foreign students, revoking their visas, often for little or no reason.

The White House has publicly justified its campaign against universities as a reaction to uncontrolled “anti-Semitism” and the desire to reverse diversity programs aimed at addressing historical oppression of minorities.

The administration claims protests against Israel’s war in Gaza that swept across US college campuses last year were rife with anti-Semitism.

Harvard lawsuit

Many US universities, including Harvard, cracked down on the protests over the allegations at the time.

Several top institutions, including Columbia University, have also bowed to demands from the Trump administration, which claims that the educational elite is too left-wing.

In the case of Harvard, the White House is seeking unprecedented levels of government control over admissions and hiring practices at the country’s oldest and wealthiest university.

But Harvard rejected the government’s demands, prompting the Trump administration last week to order the freezing of $2.2 billion in federal funding to the institution.

In its lawsuit, Harvard calls for the freezing of funds and conditions imposed on federal grants to be declared unlawful, as well as for the Trump administration to pay the institution’s costs.

The Department of Homeland Security has also threatened Harvard’s ability to enroll international students unless it turns over records on visa holders’ “illegal and violent activities.”

International students made up 27.2 percent of Harvard’s enrollment this academic year, according to its website.